A Step Toward High Temperature Intelligent Power Modules Using 1.5kV SiC-BJT

Abstract

Looking back to the development of inverters using SiC switches, it appears that SiC devices
do not behave like their silicon counterparts. Their ability to operate at high temperature makes
them attractive. Developing drivers suitable for 200 °C operation is not straightforward. In a perspective
of high integration and large power density, it is wise to consider a monolithic integration of the
driver parts for the sake of reliability. Silicon is not suitable for high ambient temperature; silicon-oninsulator
offers better performances and presents industrial perspectives.
The paper focuses on a SiC BJT driver: it processes logical orders from outside, drives adequately
the BJT to turn it either on or off, monitors the turn-off and turn-on state of the device, and acts accordingly
to prevent failure. SiC BJT imposes specific performances different from the well known
ones of SiC JFET or MOSFET. The paper addresses a preliminary analysis of a SOI driver, anticipating
the behavior of SiC-BJT and the change in behavior at high temperature. A discret driver has
been designed and fabricated. Elementary functional blocks have been validated, and a BJT converter
successfully operated at high temperature with high efficiency ( = 88%).